Got 1300 hours in this shit, got to legendary eagle master, 10 years of counterstrike. Got some tips for the beginners, might be common sense for some.

Would recommend you guys to learn the CZ75, its pretty OP if you know how to use it and it costs basically nothing.

Also you are much more likely to climb the ladder if you get together and find a team or some teammates that aren't critically retarded.

Don't play Mirage or Train, only sweaty nerds play those maps and they will take the victory easy.

Don't fight about positions, whose covering B or A. If they want your usual spot let them have it.

Eco 2nd round if you loose the first round, going counter-buy is a retarded strategy. If your teammates buy at the 2nd round after a loss just quit the game.
The only exception for this is if you are terrorist and you go eco and are able to plant the bomb first round, then you will have enough cash to buy 2nd round (although you don't have to)

If a teammate have less than 3000$ don't buy, rather go eco. (exception is 2nd round or last round or if your retarded teammate bought the round before without anyone else doing it, or if anyone can drop him a weapon)

Never buy shotguns or any SMGs except for P90, unless its the last round. You might think its a good idea but the likely-hood that its worth the cost is slim.

Play FFA deathmatch a lot, it will make your aim sky-rocket really fast, much faster than it will in any other mods. Its really nice to play a round of FFA deathmatch before queuing competitive match-making.

Play only AWP or leave it alone totally. Don't go half AWP half AK, if you go exclusively for being a AWPer you will be much better at it than if you are a jack of all trades. Every team needs an AWPer, one that you throw your acquired AWPs to at the beginning of the round, one that only uses AWP.

Never spray with your gun at long-range, rather tap 3 and 3 bullets (some prefer 2 and 2 or just single tap, that is personal preference)

Spraying into a wall will show you the spray pattern of a gun, use this if you want to get better spray-control. Adding a lot of bots against you on a singleplayer server is also good, how many bots can you spray down in 1 magazine?

you will be able to see through walls and you can practice where you can shoot through walls or not (ultra try-hard mode, this only works in singleplayer or special servers, its not hacking)

If your teammates say a lot of "OH MY GOD" "HE IS B, B BB B B B B B, HE IS BBB" or "you are noob dumb ass noob noob motherfucker cyka blyat" just mute them instantly, they will ruin your chances of winning faster than you can say cornbread.

Don't buy or open weaponcases with keys, its never worth it. You might get lucky but the likelyhood of you getting something worthwhile is really really slim. If you want a nice item just buy it on the market instead. (unless you need the thrill of opening cases)